Method and system using quality of service information for influencing a user's presence state

TECHNICAL FIELD OF THE INVENTION

This invention relates in general to communication systems and, more particularly, to a method and system using Quality of Service information for influencing a user's presence state.

BACKGROUND OF THE INVENTION

The field of communications has become increasingly important in today's society. In particular, the ability to quickly and effectively interact with an individual (through any suitable communications media) presents a significant obstacle for component manufacturers, system designers, and network operators. This obstacle is made even more difficult due to the plethora of diverse communication technologies (e.g. Instant Messaging, cellular communications, simple voice sessions, etc.) that exist in the current marketplace.

As new communication platforms (such as session initiation protocol (SIP), for example) become available to the consumer, new protocols need to be developed in order to optimize this emerging technology. For example, where a user is associated with multiple endpoints, it can be anticipated that one endpoint may be more amenable to the establishment of a communication session than others. For example, the quality of service that may be established over one endpoint may be better than that available over other endpoints. In addition, some endpoints, such as Videophones, may have different quality of service requirements than other endpoints, such as instant messaging clients. Current communication systems do not provide a user with valuable quality of service information for the establishment of communication sessions. This deficiency presents an obstacle for any employee, employer, individual, or endpoint that seeks to execute successful and productive communication sessions.

SUMMARY OF THE INVENTION

The present invention provides a method and system for the selective establishment of a communication session that substantially eliminates or reduces at least some of the disadvantages and problems associated with previous methods and systems.

In accordance with a particular embodiment of the present invention, a method using Quality of Service (QoS) information to influence a user's presence state is provided that includes the establishment of a virtual communication session between a first network device and a second network device. The virtual communication session emulates a communication session that may be established in the future. At least one QoS parameter associated with the virtual connection is monitored. Presence information is then provided to a first user that includes the QoS parameter.

Certain embodiments of the present invention may provide a number of technical advantages. For example, according to one embodiment of the present invention, an architecture and a process are provided that allow for the continuous monitoring of QoS information associated with a plurality of endpoints. A further technical advantage may be the displaying of presence information that includes the QoS information to an end user. As a result, the initiator of a communication session may make meaningful decisions about the efficiency or practicability of establishing a communication session with another end user. As a further advantage, because presence information is made available to the initiator of the communication session, the initiator may make such decisions prior to the initiation of the communication session.

Moreover, as a result of the continuous monitoring of QoS information, higher quality communication sessions may be established between two end users. As a result, a higher number of successful calls may be completed, which vastly improves efficiency parameters (particularly in the workplace). Additionally, endpoints that are not able to achieve a desired QoS may be shown as “not present” to identify the endpoints as unable to establish meaningful communication sessions.

Other technical advantages will be readily apparent to one skilled in the art from the following figures, descriptions and claims. Moreover, while specific advantages have been enumerated above, various embodiments may include all, some or none of the enumerated advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and its advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:

<figref idrefs="DRAWINGS">FIG. 1</figref> illustrates a communication system using Quality of Service information to influence a user's presence state in accordance with a particular embodiment of the present invention;

<figref idrefs="DRAWINGS">FIG. 2</figref> illustrates a presence server of <figref idrefs="DRAWINGS">FIG. 1</figref> in more detail, illustrating aspects of the present invention; and

<figref idrefs="DRAWINGS">FIG. 3</figref> illustrates an example method using Quality of Service information to influence a user's presence state, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

<figref idrefs="DRAWINGS">FIG. 1</figref> illustrates a communication system <b>30</b> for providing Quality of Service (QoS) information in conjunction with presence information in accordance with a particular embodiment of the present invention. System <b>30</b> includes a plurality of endpoints <b>32</b><i>a</i>-<b>32</b><i>d </i>having the ability to establish communication sessions between each other, using one or more of communication networks <b>34</b><i>a</i>-<b>34</b><i>c</i>. In particular embodiments, system <b>30</b> also includes a presence server <b>38</b> that operates to manage presence information for the plurality of endpoints <b>32</b><i>a</i>-<b>32</b><i>c</i>. For example purposes, assume endpoint <b>32</b><i>a </i>is associated with a first user and that endpoints <b>32</b><i>b</i>-<b>32</b><i>c </i>are associated with a second user. Thus, the first user may use endpoint <b>32</b><i>a </i>to establish a communication session with the second user. Whether the communication session is established between endpoint <b>32</b><i>a </i>and endpoint <b>32</b><i>b </i>or endpoint <b>32</b><i>a </i>and endpoint <b>32</b><i>c </i>is determined by the availability of the second user and, to some degree, the discretion of the first user due to the availability of presence information. In particular embodiments, the first user may select which endpoint <b>32</b><i>b </i>or <b>32</b><i>c </i>to reach the second user based on the QoS information available with respect to each endpoint <b>32</b><i>b </i>and <b>32</b><i>c. </i>

It will be recognized by those of ordinary skill in the art that endpoints <b>32</b><i>a</i>-<b>32</b><i>d</i>, presence server <b>38</b>, and/or gateway <b>40</b> may be any combination of hardware, software, and/or encoded logic that provides communication services to a user. For example, each endpoint <b>32</b><i>a</i>-<b>32</b><i>d </i>may include a telephone, a computer running telephony software, a video monitor, a camera, an IP phone, a cell phone or any other communication hardware, software, and/or encoded logic that supports the communication of packets of media (or frames) using communication networks <b>34</b><i>a</i>-<b>34</b><i>c</i>. Endpoints <b>32</b><i>a</i>-<b>32</b><i>d </i>may also include unattended or automated systems, gateways, other intermediate components, or other devices that can establish media sessions. Although <figref idrefs="DRAWINGS">FIG. 1</figref> illustrates a particular number and configuration of endpoints, presence servers, segments, nodes, and gateways, communication system <b>30</b> contemplates any number or arrangement of such components for communicating media. Furthermore, the endpoints <b>32</b> of system <b>30</b> may be associated with any number of users.

As illustrated, system <b>30</b> includes three communication networks <b>34</b><i>a</i>-<b>34</b><i>c</i>. The term “communication network” should be interpreted as generally defining any network capable of transmitting audio and/or video telecommunication signals, data, and/or messages, including signals, data or messages transmitted through text chat, instant messaging and e-mail. Generally, communication networks <b>34</b><i>a</i>-<b>34</b><i>c </i>provide for the communication of packets, cells, frames, or other portions of information (generally referred to as packets herein) between endpoints <b>32</b><i>a</i>-<b>32</b><i>d</i>. Communication links <b>42</b><i>a </i>and <b>42</b><i>b </i>couple communication networks <b>34</b><i>a </i>and <b>34</b><i>b</i>, and communication networks <b>34</b><i>a </i>and <b>34</b><i>c</i>, respectively. Accordingly, users of endpoints <b>32</b><i>a</i>-<b>32</b><i>d </i>can establish communication sessions between and among each network component coupled for communication with one or more of networks <b>34</b><i>a</i>-<b>34</b><i>c</i>. A call admission control (CAC) system <b>44</b> may be used to monitor the amount of bandwidth available over communication networks <b>34</b><i>a</i>-<b>34</b><i>c. </i>

In the illustrated embodiment, communication network <b>34</b><i>a </i>is a local area network (LAN) that enables communication between a plurality of endpoints <b>32</b><i>a</i>-<b>32</b><i>d </i>distributed across multiple cities and geographic regions. Communication network <b>34</b><i>b </i>is a public switched telephone network (PSTN) and couples endpoint <b>32</b><i>a </i>with communication network <b>34</b><i>a </i>through gateway <b>40</b>. Communication network <b>34</b><i>c </i>is another LAN, which couples endpoints <b>32</b><i>a </i>and <b>32</b><i>d </i>with communication network <b>34</b><i>a</i>. Communication link <b>42</b><i>b </i>is a wide area network (WAN), which couples LANs <b>34</b><i>a </i>and <b>34</b><i>c</i>. However, the described communication networks <b>34</b><i>a</i>-<b>34</b><i>c </i>are merely provided as an example configuration of communication networks. It is recognized that any one of networks <b>34</b><i>a</i>-<b>34</b><i>c </i>may be implemented as a local area network (LAN), wide area network (WAN), global distributed network such as the Internet, Intranet, Extranet, or any other form of wireless or wireline communication network.

In a particular embodiment, communication network <b>34</b><i>a </i>employs voice communication protocols that allow for the addressing or identification of endpoints and other network devices coupled to communication network <b>34</b><i>a</i>. For example, using Internet protocol (IP), each of the components coupled together by communication network <b>34</b><i>a </i>in communication system <b>30</b> may be identified in information directed using IP addresses. In this manner, network <b>34</b><i>a </i>may support any form and/or combination of point-to-point, multicast, unicast, or other techniques for exchanging media packets among components in communication system <b>30</b>. Any network components capable of exchanging audio, video, or other data using frames or packets, are included within the scope of the present invention.

Network <b>34</b><i>a </i>may be directly coupled to other IP networks including, but not limited to, another LAN, or the Internet. Since IP networks share a common method of transmitting data, telecommunication signals may be transmitted between telephony devices located on different, but interconnected, IP networks. In addition to being coupled to other IP networks, communication network <b>34</b><i>a </i>may also be coupled to non-IP telecommunication networks through the use of interfaces or components, for example gateway <b>40</b>. In the illustrated embodiment, communication network <b>34</b><i>a </i>is coupled with PSTN <b>34</b><i>b </i>through gateway <b>40</b>. PSTN <b>34</b><i>b </i>includes switching stations, central offices, mobile telephone switching offices, pager switching offices, remote terminals, and other related telecommunications equipment that are located throughout the world. IP networks transmit data (including voice and video data) by placing the data in packets and sending each packet individually to the selected destination, along one or more communication paths. Unlike a circuit-switched network (like PSTN <b>34</b><i>b</i>), a dedicated circuit is not required for the duration of a call or fax transmission over IP networks.

Technology that allows telecommunications to be transmitted over an IP network may comprise Voice over IP (VoIP), or simply Voice over Packet (VoP). In the illustrated embodiment, endpoint <b>32</b><i>d </i>and gateway <b>38</b> are IP telephony devices. IP telephony devices have the ability of encapsulating a user's voice (or other input) into IP packets so that the voice can be transmitted over network <b>34</b><i>a</i>. IP telephony devices may include telephones, fax machines, computers running telephony software, nodes, gateways, or any other device capable of performing telephony functions over an IP network.

In particular embodiments, communication system <b>30</b> may receive and transmit data in a session initiation protocol (SIP) environment. SIP is an application-layer control protocol that includes primitives for establishing, modifying, and terminating communication sessions. SIP works independently of underlying transport protocols and without dependency on the type of session that is being established. SIP also transparently supports name mapping and redirection services, which support personal mobility.

In particular embodiments, users of endpoints <b>32</b><i>a</i>-<b>32</b><i>d </i>may be identified by components of system <b>30</b> according to a uniform reference identifier (URI), such as a user's email address, or other suitable identifier so that a user may be located, monitored, and/or contacted through presence detection technology. Presence detection technology allows end users to maintain a single externally visible identifier regardless of their network location. For example, SIP features enable endpoints <b>32</b><i>a</i>-<b>32</b><i>d </i>to discover one another and to agree on a characterization of a session they would like to share. For locating prospective session participants, and for other functions, SIP enables the creation of an infrastructure of network hosts, such as presence server <b>38</b>, to which users of endpoints <b>32</b><i>a</i>-<b>32</b><i>d </i>can send registrations, invitations to sessions, and other requests.

Components of system <b>30</b> may capture information about various communication devices, or endpoints, available to a user and their status, such as whether a cellular phone is switched on or whether a user is logged into a personal computer (PC). Specifically, the SIP technology allows users of endpoints <b>32</b><i>a</i>-<b>32</b><i>d </i>to query for the presence of a particular user of an end point <b>32</b>. This would provide a presence availability status for the end user, as well as location information, device information, and any personal presence status that an end user wishes to communicate to other end users. Hence, communication system <b>30</b> builds on existing SIP capabilities and, further, extends them to provide enhanced information to a calling party. This may be achieved using a VoIP platform. The versatility of the presence detection technology, however, enables it to be used in both IP components, such as IP phone <b>32</b><i>d</i>, and other non-IP components, such as components of PSTN <b>34</b><i>b. </i>

In particular embodiments, SIP may also include primitives supporting session setup capabilities. In an example scenario, a first end user of endpoint <b>32</b><i>a </i>may desire to establish a communication session with a second end user. As described above, the second end user may be associated with endpoint <b>32</b><i>b </i>and endpoint <b>32</b><i>c</i>. In accordance with the teachings of the present invention, communication system <b>30</b> offers an interface on endpoint <b>32</b><i>a </i>that may be displayed to the first end user to facilitate the establishment of an optimum call session between the respective parties. Specifically, the interface may display presence information for the second end user. The presence information may identify the endpoints <b>32</b><i>b </i>or <b>32</b><i>c </i>through which the second user is available as well as the QoS associated with the respective endpoints <b>32</b><i>b </i>and <b>32</b><i>c</i>. Thus, the architecture of communication system <b>30</b> allows the first end user of endpoint <b>32</b><i>a </i>to make a proactive or real time decision about the establishment of a communication session before the communication session is initiated from endpoint <b>32</b><i>a. </i>

The QoS information provided to the first end user of endpoint <b>32</b><i>a </i>may include measures of the quality of service available on endpoints <b>32</b><i>b </i>and <b>32</b><i>c</i>. While QoS is difficult to define in any context, QoS may include performance parameters associated with a communication session. The QoS of digital circuits, such as endpoints utilizing ATM or VoIP, may include specific error conditions that are assigned and compared. The performance parameters considered in determining QoS for an ATM communication session include cell error ratio (CER), severally errored cell block ratio (SECBR), cell loss ratio (CLR), cell misinsertion rate (CMR), cell transfer delay (CTD), mean cell transfer delay (MCTD) and cell delay variability (CDV). Unfortunately, IP, with a connectionless, “best effort” delivery model, does not guarantee delivery of packets in order, in a timely manner, or at all. In order to obtain an acceptable level of quality, certain bandwidth, latency, and jitter (delay variation), and packet loss requirements must be met that allows multimedia IP traffic to coexist with traditional data traffic on the same network.

For providing QoS information to an end user, presence server <b>38</b> or another network device may include appropriate software, hardware, and/or encoded logic for measuring QoS information for any number of endpoints <b>32</b> in system <b>30</b>. Because the QoS information is made available to an end user of endpoints <b>32</b><i>a</i>-<b>32</b><i>d </i>before a communication session is established, however, presence server <b>38</b> may be said to measure QoS for a virtual communication session. The virtual communication session emulates an actual communication session that might be established between two endpoints should the end users of the respective endpoints elect to do so.

In particular embodiments, the virtual communication session may be established between two endpoints <b>32</b>. Thus, this type of virtual session may be referred to as an end-to-end virtual session. Returning to the example scenario described above, where first end user at endpoint <b>32</b><i>a </i>desires to establish a voice communication session with a second end user associated with endpoint <b>32</b><i>b</i>, which comprises a telephone, and endpoint <b>32</b><i>c</i>, which comprises a computing device, a virtual communication session may be established between the respective endpoints. Thus, a first virtual communication session may be established between endpoint <b>32</b><i>a </i>and endpoint <b>32</b><i>b</i>, and a second virtual communication session may be established between endpoint <b>32</b><i>a </i>and endpoint <b>32</b><i>c</i>. Each of the virtual communication sessions may include the transmission of test packets of a similar type media. Accordingly, where a voice communication session is desired, voice packets may be transmitted between the respective endpoints. The Qos of each of the virtual communication sessions may then be measured and the information incorporated into the presence information managed by presence server <b>38</b>.

In other embodiments, a single virtual communication session may be established to represent the virtual sessions between an endpoint and multiple other endpoints. This type of virtual session may be referred to as segmented virtual session. A segmented virtual session may be more practical than an end-to-end virtual session where real time or near real time QoS information is desired for a number of endpoints or combinations of endpoints. To avoid the establishment of many similar virtual communication sessions, a virtual communication session may be established between an endpoint and a centralized presence server or other centralized agent. For example, if first end user at endpoint <b>32</b><i>a </i>desires to establish a voice communication session with endpoint <b>32</b><i>b </i>and/or endpoint <b>32</b><i>c</i>, a virtual communication session may be established between endpoint <b>32</b><i>a </i>and a presence server or other agent associated with endpoints <b>32</b><i>b </i>and <b>32</b><i>c</i>. The segmented approach to virtual session processing assumes that if that the QoS between endpoint <b>32</b><i>a </i>and the presence server or other agent for endpoints <b>32</b><i>b </i>and <b>32</b><i>c </i>is good, the QoS between the respective endpoints will also be good.

After QoS information is gathered for the endpoints <b>32</b> (using either an end to end or segmented approach), the QoS information is stored in presence server <b>38</b>. The first end user of endpoint <b>32</b><i>a </i>may access presence information for the second end user and the associated endpoints <b>32</b><i>b </i>and <b>32</b><i>c </i>prior to the establishment of the voice communication session. Depending upon the particular embodiment implemented, the presence information may be displayed to the first end user over a display associated with endpoint <b>32</b><i>a</i>, a computer, or another network device. The presence information displayed to the first end user may indicate that the second end user is available to take a call on endpoint <b>32</b><i>b </i>or to receive an instant message or email message on endpoint <b>32</b><i>c</i>. The first end user may then use this information to determine the endpoint <b>32</b><i>b </i>or endpoint <b>32</b><i>c </i>with which first end user should seek to initiate a communication session.

In particular embodiments, DiffServe markings may be used in the transmission of test packets to obtain a better estimate of the QoS of a virtual communication session. DiffServe markings help to differentiate between multiple traffic flows. Specifically, the test packets are “marked” in a manner that enables routers and switches to make decisions based on those markings. The markings alter bits (for example, bits in the type of service (ToS) byte) within a frame, cell, or packet to indicate how the network should treat that traffic. In particular embodiments, the DiffServe markings may include IP Precedence or Differentiated Service Code Point (DSCP) markings. Although the markings alone do not change how network <b>30</b> treats the test packets, other tools, such as queuing tools, may reference the markings and make decisions based on them. For example, the markings may be used to make dropping or forwarding decisions. Because DiffServe does not make an explicit reservation for the future communication session, however, it may be called “Soft QoS.”

Other methods may also be used by presence server <b>38</b> to measure the QoS of the virtual communication session. For example, a reservation may be formed using IntSrv. IntSrv (also known as Integrated QoS and Inteservices) is used to make bandwidth reservations for a future communication session. In particular embodiments, presence server <b>38</b> uses IntSrv signaling among endpoints <b>32</b><i>a</i>-<b>32</b><i>d </i>to provide bandwidth reservations. Resource Reservation Protocol (RSVP) is an example of an IntServe approach to QoS. Where presence server <b>38</b> implements IntSrv to make strict bandwidth reservations, presence server <b>38</b> may be said to provide “Hard QoS.” information.

In still other embodiments, presence server <b>38</b> may obtain information from CAC system <b>44</b> to provide QoS information for endpoints <b>32</b><i>a</i>-<b>32</b><i>d</i>. As described above, CAC system <b>44</b> monitors the amount of bandwidth available over WAN <b>42</b><i>b</i>. Generally, CAC system <b>44</b> counts communication sessions in progress on a network in system <b>30</b> and determines whether the networks can handle any additional communication sessions. Presence server <b>38</b> may translate the information provided by CAC system <b>44</b> to provide QoS information for an endpoint <b>32</b>.

The QoS information gathered by presence server <b>38</b> using any of the above or other known techniques may be provided to end users for the selective establishment of communication sessions. Stated differently, an end user who desires to initiate a communication session with another end user may access presence information and QoS information to determine the endpoints that can communicate the most effectively. Thus, in particular embodiments, the QoS information may rate or otherwise qualify the prospective communication sessions between two endpoints. In other embodiments, if the QoS over a virtual communication session is identified as being too poor for the establishment of an effective communication session, the QoS information may identify one or both of the respective endpoints as unavailable. For example, if gateway <b>40</b> has failed, trunk lines are down, or another component of PSTN network <b>34</b><i>b </i>has failed, endpoint <b>32</b><i>b </i>may be identified to other end users as unavailable.

<figref idrefs="DRAWINGS">FIG. 2</figref> illustrates presence server <b>38</b> in more detail, in accordance with a particular embodiment of the present invention. Examples of presence servers include presence servers as defined by Internet Society, such as in RFC2778. Specifically, presence server <b>38</b> is coupled to one or more presentities <b>56</b> and one or more presence watchers <b>58</b> through communication networks <b>34</b><i>a</i>-<b>34</b><i>c</i>. Interfaces <b>60</b> allow presence server <b>38</b> to obtain information from presentities <b>56</b> and provide information to presence watchers <b>58</b>. As will be described in more detail below, presentities <b>56</b><i>a</i>-<b>56</b> include end users <b>62</b><i>a</i>-<b>62</b><i>c </i>(and associated endpoints <b>64</b><i>a</i>-<b>64</b><i>d</i>) who provide presence information to presence server <b>38</b> for distribution to other end users. Conversely, presence watchers <b>58</b><i>a</i>-<b>58</b><i>c </i>include an end users <b>66</b><i>a</i>-<b>66</b><i>c </i>(and associated endpoints <b>68</b><i>a</i>-<b>68</b><i>c</i>) that receive presence information about other end users from presence server <b>38</b>. Although presentities <b>56</b> and presence watchers <b>58</b> are illustrated as being exclusive from one another, it is generally recognized that an end user and its associated endpoints may both provide information to and receive information from presence server <b>38</b>. Accordingly, any end user of presence server <b>38</b> may be both a presentity and a presence watcher.

Continuing the example scenario from above, an end user, such as first end user <b>62</b><i>a</i>, provides presence information to presence server <b>38</b> through interface <b>60</b><i>a</i>. When a presence watcher end user, such as second end user <b>66</b><i>a</i>, desires to reach first end user <b>62</b><i>a</i>, presence server <b>38</b> is used to provide presence information to second end user <b>66</b><i>a</i>. The presence information may be used by second end user <b>66</b><i>a</i>, as a presence watcher, to determine the availability of first end user <b>62</b><i>a </i>at endpoints <b>64</b><i>a </i>and <b>64</b><i>b</i>, respectively.

Processor <b>70</b>, which is illustrated as presence summarization logic <b>70</b>, may include any combination of hardware (microprocessors, controllers, or other suitable computing devices or resources), software, and/or encoded logic that may be used to monitor the presence of an end user at an endpoint. In particular embodiments, presence server <b>68</b> comprises a single computer or a group of computers that are capable of receiving presence information regarding one or more presentities, such as first end user <b>62</b><i>a</i>, and selectively provide that information to one or more presence watchers, such as second end user <b>66</b><i>a</i>. In particular embodiments, processor <b>70</b> cooperates with a memory module <b>72</b>, illustrated as presence state store <b>72</b>, to provide presence information and QoS information to presence watchers <b>58</b><i>a</i>-<b>58</b><i>c</i>, such as second end user <b>66</b><i>a. </i>

Generally, processor <b>70</b> may detect the presence of end users <b>62</b><i>a</i>-<i>c </i>at endpoints <b>64</b><i>a</i>-<b>64</b><i>c</i>. For example, processor <b>70</b> may receive presence information from one or more of presence clients <b>74</b><i>a</i>-<b>74</b><i>c </i>at the end user's endpoint <b>64</b><i>a</i>-<b>64</b><i>c</i>, for example, at the end user's PC, phone, personal digital assistant (PDA) or any other presence client device (e.g., presence clients <b>74</b><i>a</i>-<b>72</b><i>c</i>). In particular embodiments, for example, presence clients <b>74</b> include software or hardware embodied in a telecommunications switch that determines the hook status of a telephone or other device. In other embodiments, presence clients <b>74</b> include software that monitor whether an endpoint comprising a computer is logged into. In still other embodiments, presence clients <b>74</b> comprise a device that communicates with an ID tag worn by an end user <b>62</b> to indicate the location of end user <b>62</b>. However, although particular presence clients <b>74</b> are described, a variety of presence clients <b>74</b> may be utilized according to the teachings of the invention to provide presence information regarding the availability, location, or activity in which an end user <b>62</b> is engaged.

In particular embodiments, the presence information obtained about an end user <b>62</b> includes the “state” of that end user <b>62</b>. End users <b>62</b> may be placed in various states, such as a “ready” state, a “not ready” state, and a “talking” state, according to the current status of the endpoint <b>64</b> with respect to presence server <b>38</b>. For example, an end user <b>62</b> in a ready state may be ready and able to accept an incoming call. Accordingly, such an end user <b>62</b> may be said to be “available.” Conversely, an end user <b>62</b> in a not ready state may be away from his desk or otherwise not ready to accept an incoming call, and an end user <b>62</b> in a talking state may currently be communicating on an incoming or outgoing call. In either case, the end user <b>62</b> may be said to be “unavailable.”

To provide presence information to presence watchers, such as end users <b>68</b><i>a</i>-<b>68</b><i>c</i>, processor <b>70</b> may access data in memory module <b>72</b>. Memory module <b>72</b> may be any form of volatile or non-volatile memory including, without limitation, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), removable media, or any other suitable local or remote memory component.

In particular embodiments, memory module <b>72</b> includes a list for some or all of end users <b>62</b><i>a</i>-<i>c </i>and <b>66</b><i>a</i>-<b>66</b><i>c</i>. The lists may include subscription lists, buddy lists, or other association information. For example, rather than make presence information for every end user <b>62</b><i>a</i>-<b>62</b><i>c </i>and <b>68</b><i>b</i>-<b>68</b><i>c </i>within system <b>30</b> available to second end user <b>66</b><i>a</i>, first end user <b>62</b><i>a</i>, as a presentity, may subscribe to a presence service. Accordingly, the subscription may identify to whom first end user <b>68</b><i>a </i>wants his presence information made available to and to what extent such information should be available. Thus, in a particular embodiment, first end user <b>62</b><i>a </i>may exert an amount of control over his own presence information. Additionally or alternatively, second end user <b>66</b><i>a</i>, as a presence watcher, may be required to subscribe to receive presence information. Thus, the subscription lists, buddy lists, or other association information may also or alternatively identify those end users <b>62</b><i>a</i>-<b>62</b><i>c </i>for which second end user <b>66</b><i>a </i>would like to receive presence information.

In the example scenario where second end user <b>66</b><i>a </i>desires to initiate a communication session with first end user <b>62</b><i>a</i>, second end user <b>66</b><i>a </i>may obtain presence information for all end users <b>62</b><i>a</i>-<i>c </i>on the subscription or buddy list of second end user <b>66</b><i>a</i>. Accordingly, if second end user <b>66</b><i>a </i>has subscribed only to receive presence information for first end user <b>62</b><i>a</i>, presence server <b>38</b> will only make presence information for first end user <b>62</b><i>a </i>available to second end user <b>66</b><i>a</i>. Presence information for a third end user <b>62</b><i>b </i>and a fourth end user <b>62</b><i>c </i>will not be made available to second end user <b>66</b><i>a</i>. Before establishing a communication session with first end user <b>62</b><i>a</i>, second end user <b>66</b><i>a </i>may reference the presence information associated with first end user <b>62</b><i>a </i>to determine whether second end user <b>66</b><i>a </i>should initiate a communication session with first end user <b>62</b><i>a </i>through endpoint <b>62</b><i>a </i>or endpoint <b>64</b><i>b</i>. For example, second end user <b>66</b><i>a</i>, as a presence watcher, may use the information to determine whether he should send first end user <b>62</b><i>a </i>an email to be delivered at endpoint <b>64</b><i>a </i>(i.e., a computer) or call first end user <b>62</b><i>a </i>on endpoint <b>62</b><i>b </i>(i.e., a telephone).

As described above, the presence information may include QoS information that indicates the quality of the communication session that can be expected if a communication session is established between any two endpoints. In the example scenario described above, the use of a subscription list or buddy list prevents presence server <b>38</b> from having to monitor QoS between all endpoints in system <b>30</b>. As described above, presence server <b>38</b> establishes a virtual connection between each endpoint to provide QoS information to second end user <b>66</b><i>a</i>. Thus, where second end user <b>66</b><i>a </i>subscribes to or is otherwise entitled to receive presence information for only first end user <b>62</b><i>a</i>, a virtual connection must be established between all endpoints <b>68</b> associated with second end user <b>66</b><i>a </i>and all endpoints associated with first end user <b>62</b><i>a</i>. Because presence information for third and fourth end users <b>62</b><i>b </i>and <b>62</b><i>c </i>is not provided to second end user <b>66</b><i>a</i>, however, a virtual connection is not established between endpoint <b>68</b><i>a </i>(associated with second end user <b>66</b><i>a</i>) and endpoints associated with third and fourth end users <b>62</b><i>b </i>and <b>62</b><i>c</i>. Accordingly, the subscription list or buddy list utilized from memory module <b>72</b> prevents system <b>30</b> from being overburdened with QoS traffic transmitted over the various communication networks <b>34</b><i>a</i>-<b>34</b><i>c. </i>

Although subscription lists and buddy lists are described above for associating users of system <b>30</b> with other users of system <b>30</b>, it is recognized that any other mechanism for the linkage or association of users may be utilized. Other example sources of association information that may be used to provide presence information include address lists or contact lists from an email program (i.e., MicroSoft Office), information provided by social networks or reputation services, or association lists such as those used by Five Degrees of Separation, Linked In, and Orchid. It is also recognized that the such mechanisms need not be stored in memory module <b>72</b> but may be stored in any component of system <b>30</b>. In particular embodiments, such mechanisms may be stored at the endpoints.

Furthermore, it will be recognized by those of ordinary skill in the art that presence server <b>38</b> is merely one example configuration of a presence server for providing presence information to end users in communication system <b>30</b>. Accordingly, it is generally recognized that presence server <b>38</b> may include any number of processors, memory modules, or other components to accomplish the functionality and features described herein. Additionally, processor <b>70</b>, and/or memory module <b>72</b> associated with presence server <b>38</b> may be centrally located (local) with respect to one another, or distributed throughout communication networks <b>34</b><i>a</i>-<b>34</b><i>c. </i>

<figref idrefs="DRAWINGS">FIG. 3</figref> illustrates an example method for providing presence information including QoS information for a plurality of users, in accordance with an embodiment of the present invention. The method begins at step <b>300</b> with the storing of user information in a database. In particular embodiments, the user information may include subscription lists, buddy lists, address lists, contact lists, social network information, or other association information that may link a plurality of users using a network or combination of networks for communication.

At step <b>302</b>, a virtual communication session is established between at least two of the plurality of end users. For example, a virtual communication session may be established between a first network device and a second network device. In particular embodiments, the first and second network devices may comprise a first endpoint <b>32</b><i>a </i>associated with a first end user and a second endpoint <b>32</b><i>b </i>associated with a second end user, respectively. Thus, the virtual communication session may be considered end-to-end. Alternatively, the first and second network devices may comprise a first endpoint associated with a first end user and a network agent device associated with a second end user, respectively. Accordingly, the virtual communication session may be considered segmented or centralized. Whether the virtual communication session is end-to-end or segmented, the communication session is considered virtual since it is established before either of the first or second end users have taken action to establish a communication session. The virtual communication session, however, emulates a communication session that may be established between the two end users in the future.

Where either or both of the first and second end users is associated with multiple endpoints <b>32</b>, a virtual communication session may be established between each endpoint <b>32</b> associated with the first end user and each endpoint <b>32</b> associated with the second end user. For example, if endpoint <b>32</b><i>a </i>is associated with a first end user and endpoints <b>32</b><i>b </i>and <b>32</b><i>c </i>are associated with a second end user, two virtual communication sessions may be established. A first virtual communication session may be established between endpoint <b>32</b><i>a </i>and endpoint <b>32</b><i>b</i>, and a second virtual communication session may be established between endpoint <b>32</b><i>a </i>and endpoint <b>32</b><i>c</i>. In this manner, the QoS between each endpoint for all possible communication paths may be monitored.

At step <b>304</b>, at least one QoS parameter associated with the virtual connections established at step <b>302</b> may be monitored. In particular embodiments, the continuous monitoring of the QoS parameter may include the transmission of a plurality of test packets along the virtual communication session. The QoS parameter may be measured for the transmission of the plurality of test packets. Where desired, the plurality of test packets may be marked to identify the type of test packets transmitted. The marking of the plurality of test packets may result in a better estimate of the QoS parameter being measured.

In other embodiments, the continuous monitoring of the QoS associated with the virtual communication session may include forming a bandwidth reservation for a communication session that may be established in the future. In particular embodiments, the reservation may be made using IntSrv RSVP. In still other embodiments, the continuous monitoring of the QoS associated with the virtual communication session may include the counting of a plurality of communication sessions already in progress on the one or more networks of interest. A determination may then be made as whether the one or more networks can handle an additional communication session between the endpoints <b>32</b>.

At step <b>306</b>, presence information may be displayed to a user of an endpoint <b>32</b> being monitored. The presence information may include availability information associated with any of endpoints <b>32</b> being monitored. For example, if endpoint <b>32</b><i>a </i>associated with the first end user comprises a cell phone, the presence information may identify whether the first user is available to take a phone call over the cell phone. The presence information also includes the QoS parameter that has been continuously monitored. In particular embodiments, the QoS parameter may include a CER, SECBR, CLR, CMR, CTD, MCTD, or a CDV.

Some of the steps illustrated in <figref idrefs="DRAWINGS">FIG. 3</figref> may be combined, modified or deleted where appropriate, and additional steps may also be added to the flowchart. Additionally, steps may be performed in any suitable order without departing from the scope of the invention.

As indicated above, technical advantages of particular embodiments of the present invention include the continuous monitoring of QoS information associated with a plurality of endpoints. As a result, the initiator of a communication session may make meaningful decisions about the efficiency or practicability of establishing a communication session with another end user. As a further advantage, because presence information is made available to the initiator of the communication session, the initiator may make such decisions prior to the initiation of the communication session.

As a result of the monitoring of QoS information, higher quality communication sessions may be established between two end users. As a result, a higher number of successful calls may be completed, which vastly improves efficiency parameters (particularly in the workplace). Additionally, endpoints that are not able to achieve a desire QoS may be shown “as not present” or otherwise unavailable to identify the endpoints as unable to establish a meaningful communication session.

Although the present invention has been described in detail with reference to particular embodiments, it should be understood that various other changes, substitutions, and alterations may be made hereto without departing from the spirit and scope of the present invention. For example, although the present invention has been described with reference to a number of elements included within a communication system, these elements may be combined, rearranged or positioned in order to accommodate particular routing architectures or needs. In addition, any of these elements may be provided as separate external components to a communication system or to each other where appropriate. The present invention contemplates great flexibility in the arrangement of these elements as well as their internal components.

Numerous other changes, substitutions, variations, alterations and modifications may be ascertained by those skilled in the art and it is intended that the present invention encompass all such changes, substitutions, variations, alterations and modifications as falling within the spirit and scope of the appended claims.